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Topic description / abstract:
This talk will present an interpretation of the evolution of multicellular organisms based on physical inherencies of cell aggregates and the conserved, intrinsic functionalities of cells. Focusing on the metazoans, it will describe how morphological motifs across all animal phyla – tissue layers and cavities, segments, appendages – are attractor states in morphospaces of cell clusters that arose with the appearance of clade-specific toolkit molecules such as classical cadherins, Wnt, and Notch. Further, the emergence of evolutionarily optional functionally differentiated cells and organs in the animals – e.g., muscle, liver, kidney – is based on partitioning and amplification of life-sustaining processes that at the cellular level are obligatory. This is accomplished by chromatin-based, enhancer-dependent gene co-expression machinery unique to metazoans. In contrast to the gradual generation of novel forms and functions postulated by adaptationist population biological models, this newer perspective suggests that novelties arising from these material and cellular inherencies come to characterize evolutionary lineages by serving as enablements for new kinds of organismal agency. This faculty, which pertains to all living systems, is the basis of niche selection and other creative capabilities that led Richard Lewontin to speak of the organism as subject, not just object, of evolution.
Biographical note:
Stuart A. Newman is a professor of cell biology and anatomy at New York Medical College, Valhalla, New York and a member of the External Faculty of the Konrad Lorenz Institute (KLI). His early scientific training was in chemistry, but he then moved into biology, both theoretical and experimental. He has contributed to several fields, including biophysical chemistry, embryonic morphogenesis, and evolutionary theory. His theoretical work includes a mechanism for patterning of the vertebrate limb skeleton based on the physics of self-organizing systems, and a physico-genetic framework for understanding the origination of animal body plans. His experimental work includes the characterization of the biophysical process of matrix-driven cell translocation and evidence for thermogenesis-related gene loss in the origin of birds. Newman has also written on ethical and societal issues related to research in developmental biology and was a founding member the Council for Responsible Genetics (Cambridge, Mass.). He has been a visiting scientist at the Institut Pasteur, Paris, Monash University, Melbourne, Australia, the University of Tokyo, Komaba, Japan. He is editor of the KLI’s journal Biological Theory.